.controller-nav {
    position: absolute;
    left: 0;
    bottom: 30px;
    z-index: 101;

    width: 100%;

    text-align: center;
}

.controller-unit{
    display: inline-block;
    margin: 0 5px;
    width: 30px;
    height: 30px;

    text-align: center;
    vertical-align: middle;

    cursor: pointer;
    background-color:#aaa;
    border-radius:50%;

    transform: scale(0.5);
}
.is-center {
    background-color:#888;

    transform: scale(1);
    transition: transform .6s ease-in-out, background-color .3s;
}
.is-center:after {
     color: #fff;
     font-family: "icons-turn-arrow";
     font-size: 80%;
     line-height:30px;
     content: "\e600";

     -webkit-font-smoothing: antialiased;
     -moz-font-smoothing: grayscale;
 }
.is-inverse {
    background-color: #555;

    transform: rotateY(180deg);
}
